Valve assemblies are used within automotive vehicles and other apparatuses to control the flow of fluids, gasses, and other materials between various interconnected and/or communicating portions or chambers which are respectively contained and/or resident within these apparatuses.
One type of valve assembly, known as a suction control valve assembly, is typically placed within an air conditioning assembly and more particularly, within the refrigerant compressor of an air conditioning assembly of a vehicle, and operatively controls the flow of refrigerant fluid, gas, and/or vapor within the compressor.
This type of valve assembly typically includes a "mechanical type" actuator which selectively causes the valve to actuatably move between an "open" position and a "closed" position. The selective actuation of the valve assembly communicatively transfers and/or moves refrigerant fluid, gas, and/or vapor from a relatively high pressure environment or chamber to a relatively low pressure environment or chamber within the compressor, thereby substantially equalizing the pressure differential between the contained chambers.
This type of valve assembly typically includes a "bellows" valve which is selectively actuated or operatively moved between an "open" and a "closed" position, by changes in the pressure differential existing between opposed sides or portions of the valve and/or between the operatively interconnected chambers or pressure environments (e.g., the valve is "opened" by the pressure differential when the pressure differential exceeds a "predetermined value" and is "closed" by the pressure differential when the pressure differential is equal to or less than a predetermined value). While this valve assembly is relatively effective to operatively and communicatively transfer fluid, gas, and/or vapor by and between portions or chambers of the compressor, and to substantially equalize the pressure between these operatively interconnected portions or chambers, it suffers from some drawbacks which adversely effect the performance and efficiency of the compressor in which it is employed.
For example and without limitation, since this prior type of valve assembly is adapted to actuate only when a single predetermined pressure differential value exists between the operatively interconnected chambers or environments, it often causes the compressor to "run" or operate at higher than desirable rates or "capacities".
Particularly, it is often desirable to actuate the valve assembly at one or more pressure differentials which are less than this single "predetermined value" (e.g., when a lesser degree of cooling is desired). By selectively actuating the valve assembly at lesser pressure differentials, the compressor is allowed to operate at a much lower capacity, thereby conserving power and improving overall operating efficiency. Allowing a compressor to operate at a lower or reduced capacity further substantially decreases the frequency at which the electromagnetic "clutch" of the compressor, which allows the vehicle engine to operatively drive the compressor, is engaged and/or is "cycled".
Because the above-described prior type of valve assembly is not designed and/or adapted to be selectively actuatable at multiple and/or at relatively "low" pressure differential values, the compressor must often operate at capacities which are undesirably high, thereby undesirably reducing the operating efficiency of the compressor. The inability of the prior valve assembly to actuate at multiple and/or relatively "low" pressure differentials further causes unnecessary cycling of the electromagnetic clutch which causes relatively significant "loads" to be applied to the vehicle's engine, thereby adversely effecting the performance and speed of the engine and the vehicle. Moreover, since the prior valve assembly does not have a mechanism to actually move or actuate the valve, separate and apart from and/or independent of the pressure differential, the use of multiple actuating pressures is not practical.
There is therefore a need for an improved valve assembly for use in a compressor, which may be selectively actuated at multiple pressure differentials; which substantially improves the overall operating efficiency of the compressor; which allows the compressor to operate at various operating capacities; and which substantially reduces the cycling frequency of the compressor's electromagnetic clutch.